Lighting devices implemented as flexible linear modules are available on the market. Such devices also come in a “protected” version, with a flexible light engine embedded in a flexible case which may be made e.g. of polymer materials. The case protects the light engine from the outer environment, with a minor impact on light output performance.
An emerging trend in the field is the production of protected modules adapted to provide a diffused lighting: the case may perform the optical function of homogenizing luminance on the outer surface of the device, by mixing the light radiation within itself. The single sources, i.e. for example the single LEDs, may not be visible any longer, even in the near field, i.e. when observed from a short distance.
In various implementations, such a lighting device or module may be implemented so that it may be bent up-down (or front-back): for example, the light radiation sources may be arranged on a support board (e.g. a Printed Circuit Board or PCB) positioned horizontally within the case, the light radiation being emitted vertically.
In the field the trend is also emerging to produce devices as previously outlined but having a specific colour, such as blue, red, green or other colours.
In this case a possible approach involves the use of e.g. monochromatic coloured LEDs on a linear flexible PCB, while embedding the assembly into a polymer with diffusive properties.
This solution may however give rise to various drawbacks. Among them we can mention the following drawbacks:                current LED suppliers have a narrower monochromatic LED portfolio than in the case of white LEDs;        technological improvements on monochromatic LEDs are slower than on white LEDs;        monochromatic LEDs may have a bigger package size than white LEDs of equal power;        monochromatic LEDs are more expensive than white LEDs of equal power;        production results of monochromatic LEDs have a wider flux and voltage distribution than white LEDs; and        suppliers do not usually offer a narrow selection.        